#include <iostream>
#include <vector>
#include <stdint.h>
#include <functional>
#include <memory>
#include <unistd.h>
#include <unordered_map>

using TaskFunc = std::function<void()>;
using ReleaseFunc = std::function<void()>;
class TimerTask
{
    private:
        uint64_t _id;       // 定时器任务对象
        uint32_t _timeout;  //定时器任务超时时间
        bool _canceled;       //false-表示没有被取消，true-表示被取消
        TaskFunc _task_cb;  //定时器对象要执行的定时任务
        ReleaseFunc _release; //用于删除Timerwheel中保存的定时器对象信息
    public:
        TimerTask(uint64_t id, uint32_t delay, const TaskFunc &cb):
            _id(id), _timeout(delay),_task_cb(cb), _canceled(false)
        {}
        ~TimerTask()
        {
            if(_canceled == false) _task_cb();
            _release();
        }

        void Cancel() { _canceled =  true; }
        void SetRelease(const ReleaseFunc& cb) { _release = cb; }
        uint32_t DelayTime() { return _timeout; }
};

class TimerWheel
{
    private:
        using WeakTask = std::weak_ptr<TimerTask>;
        using PtrTask = std::shared_ptr<TimerTask>;
        int _tick;      //当前的秒针，走到哪里释放到哪里，就相当于执行哪里的任务
        int _capacity;  //表盘最大数量---其实就是最大延迟时间
        std::vector<std::vector<PtrTask>> _wheel;
        std::unordered_map<uint64_t, WeakTask> _timers;

    private:
        void RemoveTimer(uint64_t id)
        {
            auto it = _timers.find(id);
            if(it != _timers.end())
            {
                _timers.erase(it);
            }
        }

    public:
        TimerWheel():_tick(0),_capacity(60),_wheel(_capacity) {}
        void TimerAdd(uint64_t id, uint32_t delay, const TaskFunc& cb)
        {
            PtrTask pt(new TimerTask(id, delay, cb));
            pt->SetRelease(std::bind(&TimerWheel::RemoveTimer, this, id));
            int pos = (_tick + delay) % _capacity;
            _wheel[pos].push_back(pt);
            _timers[id] = WeakTask(pt);
        }

        //刷新/延迟定时任务
        void TimerRefresh(uint64_t id)
        {
            //通过保存的定时器对象的weak_ptr构造一个shared_ptr出来， 添加到轮子中
            auto it = _timers.find(id);
            if(it == _timers.end())
            {
                return ; //没找到定时任务，没法刷新，没法延迟
            }
            PtrTask pt = it->second.lock(); //lock获取weak_ptr管理的对象对应的shared_ptr
            int delay = pt->DelayTime();
            int pos = (_tick + delay) % _capacity;
            _wheel[pos].push_back(pt);
        }

        void TimerCancel(uint64_t id)
        {
            auto it = _timers.find(id);
            if(it == _timers.end())
            {
                return ; //没找到定时任务，没法刷新，没法延迟
            }
            PtrTask pt = it->second.lock();
            if(pt) pt->Cancel();
        }

        //这个函数应该每秒钟被执行一次，相当于秒针向后走了一步
        void RunTimerTask()
        {
            _tick = (_tick + 1) % _capacity;
            _wheel[_tick].clear(); //清空指定位置的数组，就会把数组保存的所有定时管理器对象的shared_ptr释放掉
        }
};

class Test
{
    public:
        Test() { std::cout << "构造" << std::endl; }
        ~Test() { std::cout << "析构" << std::endl; } 
};

void DelTest(Test* t)
{
    delete t;
}

int main()
{
    TimerWheel tw;
    Test* t = new Test();
    tw.TimerAdd(888, 5, std::bind(DelTest, t));

    for(int i = 0; i < 5; i++)
    {
        sleep(1);
        tw.TimerRefresh(888);//刷新定时任务
        tw.RunTimerTask(); //向后移动秒针
        std::cout<< "刷新了一下定时任务，重新需要5s中后才会销毁\n";
    }
    // tw.TimerCancel(888);
    while(1)
    {
        sleep(1);
        std::cout<< "---------\n";
        tw.RunTimerTask(); //向后移动指针
    }

    return 0;
}